Perhaps you should try some spelling variations:
ban khanh » ban hanh, ban thanh, van khanh
truc ban » thuc ban, truc dan, truc van
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
va cam » va cham, va cac, va cai
va cao » va cac, va co, va dao
ve cau » ke cau, va cau, le cau
ve cac » va cac, vien cac

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ky nang x ho. lieu ((va cam) OR (va cao)) truc ban khanh ((ve cau) or (ve cac)) theo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky nang x ho. lieu ((va cam) OR (va cao)) truc ban khanh ((ve cau) OR (ve cac)) theo.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky nang x ho. lieu ((va cam) OR (va cao)) truc ban khanh ((ve cau) or (ve cac)) theo".
• Adding a wildcard symbol may retrieve word variants: so sach ky nang x ho. lieu ((va cam) OR (va cao)) truc ban khanh ((ve cau) or (ve cac)) theo*.